如何编写仅在没有比较运算符的情况下计算结果为true的where子句中使用的函数？

My question is: In Oracle regexp_like works alone in the where clause without having to compare to 1 or 0 or a string. The function can only be called when evaluating something in a case statement or the where clause. Since it can't be described (tried searching the data dictionary for it) I'm wondering how to write a function that works the same way. In Oracle regexp_like works alo